= Solution
{c}
If $x\in A=g^{-1}(B)$ and $y\mathcal Rx$, the definition of the relation applies in particular to the fixed continuous map $g$ into the fixed Hausdorff space $Y$. It gives $g(y)=g(x)\in B$, hence $y\in A$. Thus $A$ is a union of whole equivalence classes, also called a <saturation of a subset>.
Always $A\subseteq p^{-1}(p(A))$. Conversely, a point in $p^{-1}(p(A))$ shares its class with some $x\in A$, and the preceding argument places it in $A$. Hence
$$
\boxed{p^{-1}(p(A))=A.}
$$
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